The cataplasm which has been used from of old is prepared by spreading a base containing mainly an aqueous polymer on a support such as an unwoven textile and the like. The base of the cataplasm is thick (700˜1500 g/m2). Therefore, the cataplasm is superior in adhesion to the skin. Furthermore, the initial moisture content in the base is much and the cataplasm can retain moisture-protection effects on the skin.
However, the traditional cataplasm requires a definite thickness in order to make adhesion forces exhibit. When it is applied to a much movable part like a joint, it may not follow the movement, or may be released owing to rub with cloth. When it is stuck for a long term, there is a problem that humidic retension may be lost. In order to solve these problems, it has been desired to make the cataplasm thin from the viewpoint of stability with the passage of time of the physical property and adequate improvement for the manufacturing process.
The present inventors tried to prepare thin aqueous cataplasms by using a known method for preparing cataplasms, and found as a result that these cataplasms had following demerits.
Namely, an unwoven textile and a woven textile which are well ventilated are used as a support of the traditional cataplasm and when the cataplasm is made thin, water in the cataplasm during application is evaporated by body temperature and the skin is not covered with enough moisture.
Furthermore, at the same time the base is dried by evaporation of water, and adhesion forces of the cataplasm to the skin decrease. On the other hand, adhesion to the skin extremely increases owing to solidification of the base on the applied portion and it gives pain and may occasionally give a slight injury to the skin when removing.
There are following problems: The support prepared by laminating a film having low ventilation with an unwoven textile or if necessary with an adhesive agent, by heat-fusing is inferior in flexibility and homogeneity, and the affinity of the base of the cataplasm is not enough. During application, since the cataplasm lacks in following the movement at the applied part, it is removed and when removing, the film may be tore or a part of the base remains to the skin.
Especially, any attention is not paid to the traditional cataplasms in regard to constituent of the support, constituents of the base and a combination thereof. For example, the amount of the base of the traditional cataplasms is increased (700˜1500 g/m2) to keep adequate adhesion forces, but these cataplasms are not prepared based on the plan fully suitable for thin aqueous cataplasms. Even if by simply making them thin (base 150˜500 g/m2), they-were not put in practice in the points of the simplicity of preparation, quality, skin tackiness and a change with the passage of time, or costs of preparation.